| 摘要 |
PROBLEM TO BE SOLVED: To provide a servo controller which has the high capability of coping with various defects and can perform stable servo control with high precision and a servo control method. SOLUTION: The controller has an error signal extraction part which extracts from a read signal an error signal showing the quantity of deviation of an optical pickup from a servo target value, a driving part which shifts the servo position of the optical pickup, an equalizer which generates a drive signal driving the driving part by equalizing the error signal, an integral value calculation part which calculates an integral value of the error signal for each prescribed rotational angle section of a track of a recording medium, an integral value storage part which stores respective integral values in one rotation of the recording medium, a dropout detection part which detects the read signal having a dropout, a variation quantity calculation part which compares the integral value of the rotational angle section where the dropout is generated with the stored integral value of the same rotational angle section before the dropout is generated to calculated their variation quantity, and a control part which varies equalization characteristics of the equalizer according to the variation quantity.
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